Audio in an electronic form can include noise. To a human listener, noise in audio can sound like “hissing,” “wooshing,” or unintelligible crowd noise. Many different mechanisms cause noise in audio, including random Gaussian noise generated by electrical components processing audio, air blowing on a microphone, a microphone or hydrophone detecting movement of fluids such as rain or waves, cosmic background radiation affecting electrical components processing audio, solar radiation affecting electrical components processing audio, electrical storms affecting electrical components processing audio, a vibrating machine (e.g., a fan) near a microphone, and crowds of people talking near a microphone (such as in a restaurant, club, conference hall, concert hall, etc.). Noise is a problem because it interferes with listening to meaningful information in audio. Meaningful information in audio includes speech, music, and other informative sounds. Noise is distracting and can induce a human listener to lose focus on listening to meaningful information in audio.
Conventional methods and apparatus, such as audio recording devices, audio processing devices, audio transmission devices, audio amplifying devices, and audio reproduction devices may not be sufficiently equipped to mitigate effects of noise. Further, some conventional devices may impart undesirable acoustic effects into processed audio. The undesirable acoustic effects may include at least one of ringing, hissing, wooshing, reduced audio amplitude at least at one frequency, or increased audio amplitude at least at another frequency. Accordingly, there are previously unaddressed and long-felt industry needs for methods and apparatus which improve upon conventional methods and apparatus.